In his chemistry class, Kevin took 4 tests. His scores were 86, 89, 98, and 75. What was his average score on the tests?
Solution: The average is the sum of his scores divided by the number of scores. There are 4 scores and their sum is $86 + 89 + 98 + 75 = 348$ His average score is $348 \div 4 = 87$.